Abrading implements



Dec. 8"1970 w. E. suLLENBl-:RGER 3,545,142

ABRADING IMPLEMENTS Filed May 24, 1968 INVENTOR:

United States Patent 3,545,142 ABRADING IMPLEMENTS William E.Sullenberger, Rte. 1, Box 127E,

Linden, Pa. 17744 Filed May 24, 1968, Ser. N0. 731,879 Int. Cl. B24d9/02 U.S. Cl. 51-374 7 Claims ABSTRACT F THE DISCLOSURE A rotaryabrading implement composed of a mandrel having a radially expansibledrum upon which a circumferentially endless abrasive band is axiallyinsertable. The drum is characterized by a concentric outerband-supporting surface formed from axially extending flexible lingerscantilevered from the outer end of the mandrel and extending axiallyinwardly from said mandrel end. Centrifugal force generated by rotationof the drum radially expands the lingers against the intermediate innersurface of the band to anchor it in position. Additional anchorage isproduced by effecting a relatively lesser expansion of the insertionmarginal band end concurrently with said expansion at the intermediateband portion.

This invention relates to abrading implements and more particularly to arotary drum having means for securing a circumferentially endlessabrasive band thereover in a unique manner.

Heretofore, various types of flexible drums have been employed forremovably supporting endless abrasive bands thereover in tensionedposition. Patents Nos. 2,207,439 and 3,027,692 disclose typicalexamples. In such conventional types, the band is secured in position byan expansible underlying drum, made of rubber or similar llexiblematerial, against the inside surface of the band.

Although the conventional liexible or resilient drums may be perfectlyconcentric with respect to the axes of rotation before expansion, thesubsequent expansion necessary to hold the abrasive band thereover oftenproduces eccentric bulges at the abrading periphery which causes theband to wear irregularly and also sets up highly objectionablevibrations during operation.

It is therefore an object of this invention to provide an abradingimplement devoid of the aforementioned objections.

It is another object of invention to provide an abrading implementcharacterized by a rotary drum or band holder having a concentricband-receiving periphery formed upon axially extending cantileveredlingers s0 that the centrifugal force generated during rotation of thedrum will radially expand the linger surfaces outwardly into engagementwith the interior of the band to anchor the latter in position.

It is another object of invention to provide an abrading implement ofthe type described in the immediately preceding paragraph wherein thelingers are provided with means for expanding the insertion marginal endof the band a lesser amount and concurrently with the radial expansionof the intermediate band portion under the influence of said centrifugalforce to thereby additionally anchor the band in position.

It is another object of invention to provide an abrading implement Whichis simple in construction, eliicient in operation, and relativelyinexpensive to manufacture.

'Some of the objects of invention having been stated, other objects willappear as the description proceeds when taken in connection with theaccompanying drawings, in which,

ICC

FIG. l is an elevation of the invention, showing a circumferentiallyendless abrasive band mounted upon a band-receiving drum or holder;

FIG. 2 is a view of the left-hand end of FIG. l;

FIG. 3 is a view of the right-hand end of FIG. l;

FIG. 4 is an isometric view of the endless abrasive band adapted to beremovably inserted over the holder shown in FIGS. l and 2;

FIG. 5 is a view similar to FIG. 1, but showing the band in section andthe band-receiving surface of the holder in elevation;

FIG. 6 is a sectional view taken along line 6 6 in FIG. 1;

FIG. 7 is an enlarged fragmentary view of the upper portion of FIG. 6,showing the radially expanded positions of the linger and the band whensubjected to centrifugal force generated by rotation.

Referring more specifically to the drawings, the numeral 10 broadlydenotes a rotary abrading implement or tool comprising a mandrel 11having integral mounted on its outer end as at 11a a drum 12 upon whicha circumferentially endless abrasive band 13 is removably mounted.Mandrel 11 is adapted to be fastened in a machine-driven chuck (notshown) when it is desired to rotate the tool 10 during an abradingoperation.

From using endless bands such as indicated by reference character 13, ithas been found that the inside diameter for a given band size varies afew thousandths of an inch, depending upon the band grit. For example, aone-inch Llll-grit band tends to be oversize and therefore lits looselyover a one-inch drum. The oversize progressively decreases as the gritnumber increases; and thus When a slight 12C-grit band is used on `thesame mandrel, the fit is tight. The drum according to the presentinvention is designed to compensate for such variations of the banddiameter whereby a range of slightly differing band diameters may beused on the same drum.

Likewise, the roughness of the band ends or yaxial edges progressivelydecreases as the grit of the band increases. For example, a 40-grit bandhas a heavy edge, Whereas, a l20-grit band has a slight edge.Apparently, the various degrees of edge roughness are produced when thebands 13 are severed from a longer stock during manufacture.

The right-hand end of mandrel 11 (FIG. 6) penetrates bottom 12a and isprovided with an enlarged head 11a which is countersunk in the outerface of the bottom. A Washer 15 on the mandrel is pressed against theinside face of bottom 12a by means of nut 16 threadably secured upon themandrel.

By observing FIG. 6, it will be noted that drum 12 is cup-shaped andcomprises: said bottom portion or disk 12a, a continuous cylindricalWall 12b integral with and extending axially from the bottom, and aplurality of axially extending and circumferentially arranged lingers 18integral with and rigidly cantilevered from the wall. These lingers areseparated from one another by slots 19. At the respective junctions offingers 18 with wall 12b, holes 19a are provided to decrease thecross-sectional areas of the lingers which increases linger flexibilityand prevents breakage.

The outer peripheral surfaces of lingers 18, Wall 12b, and bottom disk12a are concentric with mandrel 11 and, taken together, form a tubularsurface of revolution for receiving endless band 13, said lingersurfaces being knurled as at 18a to increase the bond between thefingers and an inserted band.

Each linger 18 is provided with a shoulder 20 at its free end whichserves as a stop against which the end of an inserted band abuts whensquarely positioning the band on the holder. Adjacent the shoulders 20is a circumferential groove 21 formed in all of the fingers, said grooveserving to relieve or lessen the tension upon the rough end of the bandwhen in inserted position.

During operation, the centrifugal force generated by rotation causes thefingers 18 to expand outwardly from an approximate normal positionindicated by dotted line 25 in FIG. `6 to the bold line position to gripthe inside surface of the band. Concurrently with this expansion, therough edge or end 13a of the band expands a lesser amount and sinks intogroove 21 thereby additionally securing the band upon the outer drumsurface.

The above-described abrading drum aords the following advantages:

(a) Longer life of drum;

(b) Longer life of band;

(c) Less wear and tear on the moving parts in hand-operated machines;

(d) Endless bands will not fly apart or explode;

(e) Less 'body pressure needed to perform a grinding job andconsequently, less fatigue of the operator.

The drum bottom portion 12a is tapered or radiused inwardly as at 12a`in order to facilitate change of bands 13.

In the drawings and specification a preferred embodiment of theinvention has been disclosed, and although specific terms are employed,these are used in a generic sense and not |for purposes of limitation,the scope of invention being defined in hte Ifollowing claims.

I claim:

1. A rotary abrading implement comprising a mandrel, a circular disksecured at the outer end of said mandrel, a plurality of resilientfingers, means for rigidly cantilevering one end of each of said fingersat the circumference of said disk, said fingers extending axiallyinwardly from said mandrel end and positioned in radially spacedrelation to the mandrel, the outer surfaces of said fingers forming atubular surface of revolution substantially concentric with the mandrel,and a circumferentially endless abrasive band insertable over saidtubular surface, whereby the centrifugal force generated by rotationwill radially expand said finger surfaces radially outwardly from themandrel and against the inside surface of said band to anchor the latterin position.

2. An abrading implement as defined in claim 1 wherein saidcantilevering means includes a cylindrical wall portion integral withthe circumference of said disk and with said cantilevered finger ends,the outer surface of said wall portion being concentric with and formingan extension of said surface of revolution.

3. An abrading implement as defined in claim 2 wherein said disk isbevelled at the intersection of its outer face and the axial projectionof said outer wall surface to thereby facilitate insertion of said bandthereover and onto said surface of revolution.

4. An abrading implement as defined in claim 1 and further comprisingmeans integral with at least one of said inward linger ends and axiallyabuttable by the insertion end of said band for limiting the axialposition of the latter on said finger surfaces.

5. An abrading implement as defined in claim 4 and further comprisingmeans for relieving said insertion end portion of said band from radialexpansion, said means including a circumferential groove in said lingersurfaces underneath the abutting band end portion whereby the latterwill sink into the groove upon radial expansion of said fingers.

6. An abrading implement as defined in claim 1 and further comprisingmeans including a circumferential groove in said outer finger surfacesand substantially coinciding with an inserted band end for relieving thelatter from radial expansion by said fingers.

7. An abrading implement as defined in claim 1 wherein each of saidfingers has a reduced cross-sectional area adjacent its cantilevered endto thereby increase finger iiexibility.

References Cited UNITED STATES PATENTS 2,058,467 10/ 1936 Knowlton51-374 2,076,776 `4/ 1937 Hadaway 51-374 OTH'ELL M. SIMPSON, PrimaryExaminer

